Change User Agent in UIWebView

Question

Modern Swift

Here's a suggestion for Swift 3+ projects from StackOverflow users PassKit and Kheldar:

UserDefaults.standard.register(defaults: ["UserAgent" : "Custom Agent"])

Source: https://stackoverflow.com/a/27330998/128579

Earlier Objective-C Answer

With iOS 5 changes, I recommend the following approach, originally from this StackOverflow question: UIWebView iOS5 changing user-agent as pointed out in an answer below. In comments on that page, it appears to work in 4.3 and earlier also.

Change the "UserAgent" default value by running this code once when your app starts:

NSDictionary *dictionary = @{@"UserAgent": @"Your user agent"};
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
[[NSUserDefaults standardUserDefaults] synchronize];

See previous edits on this post if you need methods that work in versions of iOS before 4.3/5.0. Note that because of the extensive edits, the following comments / other answers on this page may not make sense. This is a four year old question, after all. ;-)

I had this problem too, and tried all methods. I found that only this method works (iOS 5.x): UIWebView iOS5 changing user-agent

The principle is to set the user agent permanently in the user settings. This works; Webview sends the given header. Just two lines of code:

NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:@"Mozilla/Whatever version 913.6.beta", @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];

Setting User-Agent, or User_Agent in the mutable request, or overriding the setValue in the NSHttpRequest by swizzling, - I tried all that and controlled the results with wireshark, and none of that seems to work, because Webview still uses the user agent value from the user defaults, no matter what you try to set in the NSHttpRequest.

It should work with an NSMutableURLRequest as Kuso has written.

NSMutableURLRequest *urlRequest = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString: @"http://www.google.com/"]];
[urlRequest setValue: @"iPhone" forHTTPHeaderField: @"User-Agent"]; // Or any other User-Agent value.

You'll have to use NSURLConnection to get the responseData. Set the responseData to your UIWebView and the webView should render:

[webView loadData:(NSData *)data MIMEType:(NSString *)MIMEType textEncodingName:(NSString *)encodingName baseURL:(NSURL *)baseURL];

Very simple in Swift. Just place the following into your App Delegate.

UserDefaults.standard.register(defaults: ["UserAgent" : "Custom Agent"])

If you want to append to the existing agent string then:

let userAgent = UIWebView().stringByEvaluatingJavaScript(from: "navigator.userAgent")! + " Custom Agent"
UserDefaults.standard.register(defaults: ["UserAgent" : userAgent])

Note: You may will need to uninstall and reinstall the App to avoid appending to the existing agent string.